Electromagnetically resettable defect detecting sensor means for deactivating mechanically operable sensor switch

ABSTRACT

An apparatus for detecting defects in a tow wherein a sensing portion of the apparatus in contact with the tow is movable by small imperfections in the tow to shut down the tow driving mechanism. The sensing element is mounted on a movable support member to allow additional movement of the sensing element when it is engaged by a knot in the tow. The sensing element is mounted in such a manner that a small amount of movement in that portion of the sensing element in contact with the tow results in a much larger movement of that portion of the sensing element which acts to shut down the drive mechanism.

United States Patent 1191 i 1111 ,821,499 3 Marsello et al. June 28,1974 [54] ELECTROMAGNETICALLY RESETTABLE 3,462,568 8/1969 Smith ZOO/6M33,577,955 5/l97l Palmer ZOO/61.42 X FOR 3,619,523 1 1/1971 Tanahe ZOO/6i.41 3,632,918 1/1972 Anson et al 200/6l.4l OPERABLE SENSOR SWITCH [75]Inventors: Bernard D. Marsello; Lindsey T. Primary Examiner-James R.Scott Matthews, both of Decatur, Ala. [73] Assignee: Monsanto Company,St. Louis, Mo. S CT [22] Filed; Feb. 13, 73 An apparatus for detectingdefects in a tow wherein a sensing portion of the apparatus in contactwith the tow is movable by small imperfections in the tow to shut downthe tow driving mechanism. The sensing e1- [2l] Appl. No.: 331,730

52 us. 01. 200/61.13, ZOO/61.41 ement is mounted on a movable pp memberto 51 1111.01. H0lh 3/16, B65h 25/14 allow additional movement 9 theSensing element 58 Field 61 Search 200/6113, 61.18, 61.41, when It ISengaged by a knot the The Sensmg 200/6142; 335/26, 27 element is mountedin such a manner that a small amount of movement in that portion of thesensing el- 5 I References Cited ement in contact with the 'tow resultsin a much larger movement of that portion of the sensing element IUNITED STATES PATENTS which acts to shut down the drive mechanism.2,960,731 11/1960 Hogg, ll. 81 al. ZOO/61.13 X

3,301,974 1/1967 Hancock, ZOO/61.13 6 Claims, 2 Drawing Figures L 115VAC It is conventional in the manufacture of man-made fibers to produceand treat the fibers in tow form prior to cutting the tow into staple.For quality control of the final product it is very desirable that thefilaments in the tow be arranged in an orderly manner. Imperfections inthe tow can cause undesirable results such as fiber length variations inthe staple cut from the tow. Imperfections in the tow may be in the formof tangled fibers, groups of fibers clumped together or even knots wheretwo tows are tied together. In order to improve the quality of thestaple it is desirable to remove these imperfections from the tow priorto the cutting operation. This can be accomplished by detecting theimperfections and manually cutting out that part of the tow containingthe imperfections.

Various approaches have been used for detecting imperfections in tows. Anumber of these approaches utilize devices wherein a sensing element ofsome type rests on the moving tow and, upon movement of the element byan imperfection in the tow, shuts down the tow feed mechanism and thetow cutter. Unfortunately, a device sensitive enough to detect a smallimperfection in the tow may be severely damaged by a large knot in thetow while a device constructed so as to be immune to damage from a largeknot may not be sensitive enough to detect a small imperfection such asa tangle. With this in mind, one of the objects of this invention is toprovide a novel and improved apparatus for detecting defects in tow.

Another object of this invention is to provide an apparatus which issensitive enough to detect a small im-- perfections in a tow yet willnot be damaged by' a large knot in the tow.

Other objects and advantages of the invention will become apparent whenthe following detailed description is read in conjunction with thedrawings, in which FIG. 2 is a fragmentary side view of that portion ofI the device which senses defects in the tow.

Referring now in detail to the drawing, there is shown a support member11 made up of a pair of bars 12 secured to a plate 13, the upper ends ofthe bars 12 being secured to a rod 16 which is pivotally attached to aframe 17. A sensing plate 20 positioned between the lower ends of thebars 12 is provided with a curved lower end 21 which is positioned toengage a tow 23 passing over a roll 24, the tow 23 being nipped betweenthe curved end 21 and the roll 24. A rod 27 secured to the sensing plate20 extends through the lower ends of the bars 12 to pivotally attach thesensing plate 20 to the support member 11.

A switch 28 secured to the plate 13 is provided with an elongatedactuating handle 29 which extends downward through an opening in aswitch actuator 31) secured to the upper end of the sensing plate 20.Nuts 33 threaded onto the switch actuator 30 and positioned on oppositesides of the sensing .plate 20 are provided for adjusting the positionof the switch actuator 30 to a point just short of opening the switch 28when tow without imperfections is passing between the end 21 and theroll 24. The switch 28 is connected to a tow cutter (not shown) and amechanism (not shown) driving the roll 24 and other feed rolls (notshown) so that when an imperfection in the tow 23 moves the sensingplate 20 to open the switch 28 the cutter and the drive mechanism willbe shut down.

A bolt 34 threaded through a nut 35 welded to the plate 13 is providedfor limiting movement of the upper end of the sensing plate 20 in adirection toward the switch 28 to thereby prevent damage of the switchwhen a large knot passes between the end 21 and the roll 24.

A bolt 41) extends through a slot 41 in a bar 42 welded to one of thebars 12 to a position behind the upper end of the sensing plate 20 tolimit movement of the upper end of the sensing plate 21) in a directionaway from the switch 28. This is to prevent damage to switch 28.

A solenoid 45 secured to the plate 13 is provided with a plunger 46which is positioned to engage the upper end of the sensing plate 20 topush this end in a direction away from the switch to thereby move theswitch handle 29 and close the switch 28. The solenoid 45 is energizedwhen a manually-operated, normally open push button switch 47 isoperated to connect a power supply to the solenoid 45.

The distance from the switch actuator 30 to the pivotal axis (rod 27) ofthe sensing plate 20is much greater than the distance from the pivotalaxis to the curved lower end 21 of the plate 20. The purpose of thisarrangement is to amplify movement of the lower end of the sensing plate211 so that a very small amount of movement, caused by a smallimperfection in the tow, of the curved end 21 results in a much largermovement of the switch actuator 30. Thus, very small imperfections inthetow can be detected.

It will be seen from FIG. 2 that the center of gravity of the sensingplate 20 is to one side of the axis of the rod 27 so that the weight ofthe plate 20 urges the curved lower end 21 into contact with the tow. Inoperation, the tow passes between the roll 24 and the lower end 21 ofthe sensing plate 20. Any imperfec tion in the tow which moves thecurved end 21 will cause the upper end of the sensing plate 21) to movetoward the switch 28 and thereby open the switch to shut down the cutterand the drive roll mechanism. The operator then manually cuts theimperfection from the tow, relaces the tow through the machine to thecutter and then presses the push button switch 47 to energize thesolenoid 45. Energization of the solenoid 45 moves the upper end of thesensing plate 20 away from the switch 28 to close the switch and therebystart up the cutter and the mechanism (not shown) driving the roll 24.

Any very large imperfection in the tow, such as a knot uniting two tows,will move the sensing plate 20 to shut down the cutter and the rolldrive mechanism as described. The knot moves the sensing plate 20 untilit engages and is stopped by the bolt 34, whereupon the entire unitpivots on the rod 16 to allow the knot to pass between the end 21 andthe roll 24. Without movement of the support member 11 the knot willbend or break the sensing plate 20 or some other part of the structure,since the roll 24 and the other rolls (not shown) driving the tow have alarge amount of inertia and are driven at a high speed. Movement of thesupport member 11 allows sufficient displacement of the lower end 21 ofthe sensing plate to allow the knot to pass between the end 21 and theroll 24 without damage to any of the apparatus, the knot stoppingshortly after this point.

What is claimed is:

1. An apparatus for detecting defects in a tow of filaments, comprisinga. a frame,

b. a support member mounted on the frame,

c. a sensing element movably mounted on the support member and having asurface in contact with the moving tow,

d. a switch mounted on the support member and positioned to be opened bythe sensing element when a defect in the tow moves the sensing element,said support member being movable on the frame to carry the sensingelement to a position to allow knots in the tow to pass the sensingelement, and

e. a solenoid mounted on the support member and positioned to engage andmove the sensing element to close the switch after it has been opened bya defect in the tow.

2. The apparatus of claim 1 wherein the sensing element is pivotallymounted on the support member on an axis positioned at a distance fromsaid surface which is less than the distance from said axis to that partof the sensing element which actuates the switch.

3. The apparatus of claim 1 wherein the sensing element is pivotallyattached to the support member and has one end in contact with the towand the other end positioned to actuate the switch, the pivotal axis ofthe sensing element being between said ends.

4. The apparatus of claim 3 wherein a switch actuator secured to saidother end of the sensing element is connected to and operates the switchwhen the sensing element is moved.

5. The apparatus of claim 4 wherein the said pivotal axis is positionedcloser to said one end in contact with the tow than to said switchactuator.

6. An apparatus for detecting defects in a tow of filaments, comprisinga. a frame,

b. a support member pivotally attached to and depending from the frame,

c. a sensing plate pivotally attached to the lower end of the supportmember and having a curved lower end positioned to engage a moving towpassing over a roll,

(1. a switch mounted on the support member,

e. an adjustable switch actuator mounted on the upper end of the sensingplate, said switch actuator being positioned to open the switch when animperfection in the tow moves the sensing plate, said switch actuatorbeing positioned at a greater distance from said pivotal axis of thesensing plate than the distance from said pivotal axis to the curvedlower end of the sensing plate to thereby amplify movement of saidcurved lower end,

f. a pair of stops mounted on the support member and positioned onopposite sides of the sensing plate for limiting movement of the switchactuator relative to the switch, and

g. means on the support member for closing the

1. An apparatus for detecting defects in a tow of filaments, comprisinga. a frame, b. a support member mounted on the frame, c. a sensingelement movably mounted on the support member and having a surface incontact with the moving tow, d. a switch mounted on the support memberand positioned to be opened by the sensing element when a defect in thetow moves the sensing element, said support member being movable on theframe to carry the sensing element to a position to allow knots in thetow to pass the sensing element, and e. a solenoid mounted on thesupport member and positioned to engage and move the sensing element toclose the switch after it has been opened by a defect in the tow.
 2. Theapparatus of claim 1 wherein the sensing element is pivotally mounted onthe support member on an axis positioned at a distance from said surfacewhich is less than the distance from said axis to that part of thesensing element which actuates the switch.
 3. The apparatus of claim 1wherein the sensing element is pivotally attached to the support memberand has one end in contact with the tow and the other end positioned toactuate the switch, the pivotal axis of the sensing element beingbetween said ends.
 4. The apparatus of claim 3 wherein a switch actuatorsecured to said other end of the sensing element is connected to andoperates the switch when the sensing element is moved.
 5. The apparatusof claim 4 wherein the said pivotal axis is positioned closer to saidone end in contact with the tow than to said switch actuator.
 6. Anapparatus for detecting defects in a tow of filaments, comprising a. aframe, b. a support member pivotally attached to and depending from theframe, c. a sensing plate pivotally attached to the lower end of thesupport member and having a curved lower end positioned to engage amoving tow passing over a roll, d. a switch mounted on the supportmember, e. an adjustable switch actuator mounted on the upper end of thesensing plate, said switch actuator being positioned to open the switchwhen an imperfection in the tow moves the sensing plate, said switchactuator being positioned at a greater distance from said pivotal axisof the sensing plate than the distance from said pivotal axis to thecurved lower end of the sensing plate to thereby amplify movement ofsaid curved lower end, f. a pair of stops mounted on the support memberand positioned on opposite sides of the sensing plate for limitingmovement of the switch actuator relative to the switch, and g. means onthe support member for closing the switch.